I was flying my Mavic Pro today with some friends, conditions were fine, winds not high, battery level was around 60 percent, and signal strength was good, showing 17 satellites. I brought it down to about 3 meters and hovered for a bit to take a few photos, then was going to demonstrate the RTH feature for my friends, who had not seen it before. Normally I wouldn’t use RTH to land but I figured it was so close at that point it would just land normally. I started RTH and the aircraft actually climbed to around 10 meters and then hit a tree branch, at which point I tried to cancel RTH, which would not cancel. The aircraft hovered above the treetops for what felt like an eternity, during which time I had no control of it and could not cancel RTH or do anything. Finally the battery level started to decrease and eventually I was able to control it again and land manually. I have 3 broken propellers, I don’t see any damage to the motors or gimbal, I’ll check it out tomorrow to make sure and I plan on contacting tech support to see if they can check the flight records to tell me what wrong. I’m also covered under DJI Care so that’s good. But I guess I’d like to know if this was due to activating RTH at a low altitude, or if this should not have happened.

When you initiate RTH the first thing your drone does is ascend to the altitude you set beforehand to ensure it won't be flying into trees.

If you hit RTH under a tree, it will fly up into the tree.

Activating RTH when a Mavic Pro is between 5 and 20 meters from the homepoint will let it ascend to 10 meter altitude before returning to home, this altitude can not be changed because its coded into the Mavic Pro. The RTH altitude which you can modify is for distances beyond 20 meter from the homepoint.
The same goes for the Mavic Air, except it ascends to 2,5 meter instead of 10 when between 5 and 20 meter from the homepoint.

Both don't have upwards object detection, so if something is above the aircraft, your toast.  As to why you couldn't regain control, really can't answer, you should be able to deactivate RTH procedure after activating.

MaineMavick Posted at 2018-2-18 20:45
When you initiate RTH the first thing your drone does is ascend to the altitude you set beforehand to ensure it won't be flying into trees.

If you hit RTH under a tree, it will fly up into the tree.

Right, it wasn’t under a tree though.

Sound like the RTH feature work exactly like it should have.

Locoman Posted at 2018-2-19 05:15
Sound like the RTH feature work exactly like it should have.

How do you mean? I get the part about climbing to 10 meters before landing, but it then moved to the side at least 3-5 meters, which is when it hit the tree branches. Also, I tried to cancel RTH at least 20 times during the next ten minutes or so, shouldn't it have canceled?

If it didn't continue to return to home for ten minutes you obviously did cancel it. Were you flying with the controller or only the phone?

ghostrdr Posted at 2018-2-19 07:35
If it didn't continue to return to home for ten minutes you obviously did cancel it. Were you flying with the controller or only the phone?

I was using the remote, with my phone connected to the remote. It kept beeping during that time and the status showed that it was in RTH mode. During that time, it hovered above the treetops and I hd no control of it. I would press the cancel RTH button on the remote or the mobile app, it would ask if I was sure, I would tap yes, then nothing happened. Finally, when the battery level reached around 20%, I was able to control it and land manually.

If 5-20m from the home point it will immediately ascend to 10m then fly forward to the home point then land using the precision landing - if that has not worked on take off the auto landing will not be as precise and this can lead to the drone landing feet rather than inches away from where it took off. Everything Losbol stated above is totally correct. As for cancelling RTH how did you attempt to do that?

A CW Posted at 2018-2-19 07:38
If 5-20m from the home point it will immediately ascend to 10m then fly forward to the home point then land using the precision landing - if that has not worked on take off the auto landing will not be as precise and this can lead to the drone landing feet rather than inches away from where it took off. Everything Losbol stated above is totally correct. As for cancelling RTH how did you attempt to do that?

I pressed the cancel RTH button on the mobile app, then confirmed. I also tried pressing the RTH button on the remote, as the manual states this will cancel it. Neither worked, after several attempts.

Well it performed perfectly up to that point but yes, it should have cancelled in a split second. It may have something to do with the crash that happened during the RTH. At least you have care refresh - wise move!

Was the tree in the way of it returning home? I don't know if, and if so, how the Mavic Pro handles obstacles when trying to return home?  A CW, do you know maybe, does it just hover at such points?

Could it be that the aircraft just wasn't been able to move due to obstacles in its way? could it be that you actually did disable the RTH sequence but after that couldn't be able to move due to obstacle avoidance taking over?

Maybe upload the log file? That's bound to give more information.

Sirecho Posted at 2018-2-19 05:03
Right, it wasn’t under a tree though.

"I started RTH and the aircraft actually climbed to around 10 meters and then hit a tree branch"

I love the inability of people on this page, to tell the truth, or properly explain anything when they crash.

I hope your claim is denied.

MaineMavick Posted at 2018-2-19 10:18
"I started RTH and the aircraft actually climbed to around 10 meters and then hit a tree branch"

I love the inability of people on this page, to tell the truth, or properly explain anything when they crash.

Thank you for confirming my suspicion that my first reply would be rude and sarcastic. So you were there now, were you? What I said is that the aircraft climbed to around ten meters, then hit a tree branch, then further explained when someone else asked (politely) that what had happened was that the aircraft flew towards the tree branch, which was not directly above it. If the tree branch had been directly above it, I would not have been curious why it hit it.

Sirecho Posted at 2018-2-19 07:38
I was using the remote, with my phone connected to the remote. It kept beeping during that time and the status showed that it was in RTH mode. During that time, it hovered above the treetops and I hd no control of it. I would press the cancel RTH button on the remote or the mobile app, it would ask if I was sure, I would tap yes, then nothing happened. Finally, when the battery level reached around 20%, I was able to control it and land manually.

The AC might have gone into Object Avoidance mode, which could explain some confusion. OA may cause the AC to move in an attempt to avoid a detected obstruction in the RTH flight path. Sadly, OA doesn't work very well with individual tree branches.

But really, as others have suggested, examining the flight log should tell you what the AC was up to.

MaineMavick Posted at 2-19 10:18
"I started RTH and the aircraft actually climbed to around 10 meters and then hit a tree branch"

I love the inability of people on this page, to tell the truth, or properly explain anything when they crash.

Surprised how insensitive people are here for drone problems of others, given it’s a DJI forum. Why you don’t believe him? Just because nothing yet happened to your drone? “Hope your claim is denied”...
I had a similar experience with my brand new Mavic Pro. I was just about to land, battery low. The drone was like three meters from the home point, so I was not worried. Suddenly, the RTH is triggered, I assume due to low battery. Ok, I let it ascend to like 10 meters hoping it will safely land itself as I saw in those videos. Instead, it started behaving as if it was on ATTI (not sure if it was actually ATTI I was too busy trying to save the drone). It was drifting  backwards into a tree, I tried to regain control, it was moving erratically, not leveled. I was able to bring it down and just land anywhere on the ground. I’m not an expert, not sure what happened but it did not return to home point as it was supposed to. I calibrated everything before the flight. Home was right below it

MaineMavick Posted at 2-19 10:18
"I started RTH and the aircraft actually climbed to around 10 meters and then hit a tree branch"

I love the inability of people on this page, to tell the truth, or properly explain anything when they crash.

Surprised how insensitive people are here for drone problems of others, given it’s a DJI forum. Why you don’t believe him? Just because nothing yet happened to your drone? “Hope your claim is denied”...
I had a similar experience with my brand new Mavic Pro. I was just about to land, battery low. The drone was like three meters from the home point, so I was not worried. Suddenly, the RTH is triggered, I assume due to low battery. Ok, I let it ascend to like 10 meters hoping it will safely land itself as I saw in those videos. Instead, it started behaving as if it was on ATTI (not sure if it was actually ATTI I was too busy trying to save the drone). It was drifting  backwards into a tree, I tried to regain control, it was moving erratically, not leveled. I was able to bring it down and just land anywhere on the ground. I’m not an expert, not sure what happened but it did not return to home point as it was supposed to. I calibrated everything before the flight. Home was right below it

What did you do to try and cancel RTH?

I`ve never had any problems when I press the "Pause" button as it then gives me time to evaluate the situation and then rectify.

HendrikJB Posted at 11-27 01:11
What did you do to try and cancel RTH?

I`ve never had any problems when I press the "Pause" button as it then gives me time to evaluate the situation and then rectify.

This is good advice.  It sounds like you did two things that should have cancelled RTH (on screen cancel and hitting RTH hard button).  This is a third thing you can try.

I usually like to land manually but if I land RTH, I always hover my finger over the Pause button so I can stop it if things aren't going well.

BKahuna Posted at 11-27 08:40
This is good advice.  It sounds like you did two things that should have cancelled RTH (on screen cancel and hitting RTH hard button).  This is a third thing you can try.

I usually like to land manually but if I land RTH, I always hover my finger over the Pause button so I can stop it if things aren't going well.

AND.....

I like to land slowly......

Hi Sirecho,

Perhaps your fightlog has more information in it...

If you like to upload your log, mayby it explains it all.
Use this > http://www.phantomhelp.com/LogViewer/Upload/

cheers
JJB

What amazes me is that people are flying UAV's without reading and understanding the manual and or trying some simulator flights first.

I think that they will be able to restore  it.but i saw that you broke three propelers maybe you have to be more careful.
regards,
Victory Rethymno

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